Chillers are equipped with gas compression systems to compress refrigerant gas for cooling purposes. These systems employ motors to drive the compression mechanism for compressing the refrigerant gases. The size and type of motor employed in a particular system depends on several factors, such as the size and type of compressor, and the operating environment of the chiller. For example, systems may employ hermetic or semi-hermetic permanent magnet motors that offer a number of benefits for applications in which an electric motor is utilized to drive a refrigerant compressor, including enhanced efficiency, power density, and speed control precision. However, such motors also present challenges in providing adequate motor cooling. The temperature of the magnetic material of such motors must be controlled to avoid damage due to elevated temperature conditions which can arise, for example, from inadequate cooling or increased stator or rotor loss.
While various systems have been employed to provide motor cooling in a chiller system, some applications present a risk of chemical or mechanical attack on the magnets and other components by, for example, readily placing refrigerant in the air gap between the rotor and stator of the motor. Other applications provide inadequate cooling of the coil heads and other areas of the motor. Still other applications incorporate cooling fins that create high velocity impingement of refrigerant on the motor coils, increasing the possibility of wearing of the motor components and pumping energy losses. Thus, there is a need for the unique and inventive systems and methods for cooling of motors employed in the gas compression system of a chiller.